A CFM for a vehicle includes an ECU, which traditionally includes a power supply circuit and a signal circuit integrated into a single printed circuit board (PCB). The power supply circuit should be carried by a thick copper foil for high conductivity. Therefore, said single PCB should include thick copper foil, resulting in an increase in cost, volume and weight of the PCB. In addition, the power supply circuit can easily cause interference to the signal circuit. Furthermore, the PCB is traditionally coated with insulting material, which increases a thermal resistance between the PCB and a heat sink mounted on the ECU for heat dissipation.